Heretofore, the techniques in which materials being processed are, for example, welded by causing the tool horns of this sort to excite ultrasonic vibrations concerned with longitudinal or torsional direction have already been widely utilized, and among them as the one causing the tool horn to generate torsional vibrations there is known the technique of Japanese Utility Model Registration Application (OPI) No. 33530/1992 (prior-known example 1).
The contents of this application are such that torsional vibrations are imparted to the input plane of the tool horn by means of a torsional vibrator and by making these torsional vibrations resonate with the frequency to be used so as to generate torsional vibrations on the radial plane of said tool horn, the materials being processed are subjected to ultrasonic processing.
Also, as the technique which utlizes the torsional vibration mode generated in an ultrasonic machine, or the like, there has been proposed that of Japanese Patent Application (OPI) No. 172577/1990 (prior-known example 2), whose contents are such that a plurality of groups of split-electrodes are juxtaposed to a piezo-electric ceramic ring, being combined in such a way that the electric force line has a definite angle of inclination against the direction of the thickness between two split-electrodes with each of them being constituted so as to facilitate the electric polarizing treatment and coupling treatment.
In addition to the above, as the technique which converts longitudinal vibrations imparted to torsional vibrations, for example, the technique concerning ultrasonic motors is shown in a Japanese book "Kyoryoku Cho-onpa Gijutsu (High-power Ultrasonic Technique)" (published Sep. 30, 1987) (conventional example).
The Contents of this book are as described on pages 370-371 of said book; that is to say, it is disclosed that as shown in FIG. 2 of said book ultrasonic vibrations concerned with longitudinal direction can be converted to torsional ultrasonic vibrations by making use of a torsional Coupler in such a way that while one said of a disk is concaved to provide a groove leaving one pair of crescent-shaped legs, the other side is protrusively provided with a beam situated in the diagonal position to said groove, so that when, supporting said disk by screwing up a bolt (not shown in the figure) into the tapped hole pierced in the central portion of said disk, longitudinal vibrations in the direction of the arrow X are applied to said crescent-shaped legs, flexural vibrations are generated in the disk, and the ridgeline of said beam tilts, and as the result torsional vibrations are generated on the upper surface of said beam.
Even in the techniques disclosed in the above-described prior-known examples 1 and 2 it is found that in the point of subjecting the materials being processed to ultrasonic machining treatment they are so original and inventive, respectively, that their objects can presumably be achieved, but in said prior-known example 1, since the input imparted is torsional vibrations it separately requires the means for generating torsional vibrations, and also in the prior-known example 2, it is indispensable for the generation of the torsional vibrations to employ a special technical means whose structure is complicated as described above, so that in either case, the scaling up and cost up of the aimed device were inevitable.
Further, the conventional example in the above-described book relates to no more than the torsional coupler per se for merely converting longitudinal vibration to torsional vibration, and therefore, from the side of the users it has been keenly hoped for that as the ultrasonic vibration tool horns there are provided those which are of a small size obtainable at low cost and can effeciently generate the power of torsional vibrations.
The object of the present invention is to provide a tool horn such that when it is only supplied with ultrasonic vibrations concerned with longitudinal direction it can serve as a compact tool horn which per se can generate power by converting said ultrasonic vibrations to torsional vibrations and when in actual use it can be readily fitted to the longitudial vibration device widely used for various purposes.